Booster child seat



FIG. 1 is a perspective view of the booster child seat showing our new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines in the Figures illustrate the remaining parts of the booster child seat and form no part of the claimed design. 

CLAIM The ornamental design for a booster child seat, as shown and described. 